Carlos Alcaraz racked up his 40th win of the year on Thursday when he defeated Norbert Gombos of Slovakia 6-2, 6-3 to begin his Umag title defence in style.
The Spaniard won his maiden title at the Croatian clay court tournament in 2021 and has returned this year as the youngest man to make the top five in the world since Rafael Nadal in 2005.
"It was a really tough match. It wasn't as easy as the result seems," said Alcaraz, who fended off seven break points against the lucky loser.
"Norbert played a really good game and the first round of every tournament is never easy, so I had to get used to the conditions. It was tough for me, but at the end I found a way to play better and get the win."
Since defeating Richard Gasquet in the Umag final last year, 19-year-old Alcaraz has added four further titles to his collection, including Masters crowns at Miami and Madrid.
Thursday's win came after a surprise weekend loss in the Hamburg final against Lorenzo Musetti.
Alcaraz, who is now 25-3 on clay this season, will face Argentina's Facundo Bagnis on Friday for a place in the semi-finals